A model for studying the effects of diabetes in pregnancy has been developed in the Rhesus primate by implantation of a minipump delivering insulin subcutaneously during the last trimester of pregnancy. The physiological and biochemical effects of chronic fetal hyperinsulinemia will be evaluated in placenta, liver, lung, muscle and adipose tissue. Neonatal homeostasis will continue to be studied in newborn lambs utilizing the prime-continuous infusion technique. Steady state insulin production will be evaluated with I131-during various steady state glucose conditions. Hemoglobin AIc will continue to be assessed in pregnancy with reference to (1) glucose control, (2) fetal growth, and (3) effects on oxygen carrying capacity and oxygen dissociation from hemoglobin.